<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>typeof方法</title>
</head>
<body>

</body>
<script>
    // typeof方法判断数据类型
    let l1 = true;
    document.write(typeof(l1) + "<br>");

    let l2 = null;
    document.write(typeof(l2) + "<br>");

    let l3 = true;
    document.write(typeof(l3) + "<br>");

    let l4;
    document.write(typeof(l4) + "<br>");

    let l5 = "hello";
    document.write(typeof(l5) + "<br>");

    let l6 = 100n;
    document.write(typeof(l6) + "<br>");
</script>
</html>